1. Field of the Invention
The present invention relates to the control device for an automatic liquid handling system that manages reaction time of reagent or enzymes that are used in drug metabolic experiments.
2. Description of Related Art
In the development of new drugs, drug metabolic experiments are frequently carried out, and each experiment is involved with a large amount of work. It is therefore essential to reduce mistakes caused by human error. To this end, human operations tend to be replaced by automatic mechanical operations.
It is important to manage a reagent reaction time in drug metabolic experiments. Japanese Patent Application Publication No. 2000-83650 discloses an automatic test apparatus used in conducting metabolic experiments. The apparatus includes a three-dimensionally movable robot having a tip end on which a single dispensing probe is mounted. With this apparatus, a solution of specimen is dripped into a reaction stop solution stored in a vial after expiration of a predetermined period of time during which reaction occurs. This period of time is specifically determined depending on the specimen subject to the experiment. Japanese Patent Application Publication No. 2000-83650 discloses setting an enzyme reaction time to be 30 minutes, 60 minutes, 120 minutes as examples. Selection of the reaction time is carried out by a program installed in a control device.
The above-described apparatus is disadvantageous in that with a single dispensing probe, a number of experiments cannot be performed at high speed. To resolve the disadvantage, recent tendency is to use microplates having wells formed in an n-by-m matrix instead of vials. The use of microplates reduces costs and the quantity of reagent. In an automatic liquid handling system using the microplates, a large number of processings involved in a drug metabolic experiment can be performed at high speed.
However, accurate and reliable experiment cannot be performed with the automatic liquid handling system using the microplates. Despite the fact that a small quantity of reagent shortens a reaction time, reaction time in different rows of the wells on the microplate varies due to variation in robot operation time, time needed for attaching and detaching the dispensing tips to and from the robot, and a work time needed for an operator to temporarily stop the robot to supplement the reagent. The above-described disadvantages are particularly fatal in the case where a desired reaction time is short or a reagent reaction time expires during the robot is executing another process.
Further problem arises such that when the system is restarted due to occurrence of operational errors or accidental power down of the system, execution of the outstanding process may be finished before or after expiration of a desired reaction time. In such cases, the results of experiment are not available and so the experiment per se is vain.